Because all cell substrates are subject to mycoplasma contamination, there is a test requirement (CFR Section 21:610.30) for the presence of mycoplasmas in all mammalian cell lines used for the production of viral vaccines for human use. There is also a requirement in the "Points to be considered" to test for mycoplasmas in other human biologics produced in cell substrates and grown in vitro, including all immune modulators, cytokines, tpa, epo, growth factors, etc. and monoclonal antibodies. As previously reported, we have maintained a continuing research program to improve existing procedures or to develop new procedures for the isolation, detection, identification and speciation of mycoplasmas isolated from contaminated and/or infected cell cultures and biologic products produced for human use. Although the incidence has varied from year to year, contamination continues today to be a major concern to the laboratory investigator and to the manufacturer of biologics. Presently, the current CFRs are being updated and revised because of the advancements in the laboratory science dealing with test procedures. The Laboratory is monitoring the literature on the use of the new generation of high-tech detection procedures, such as the use of DNA and immunological probes, PCR, etc. and is initiating research programs to evaluate the usefulness of these sophisticated procedures for detecting mycoplasmas in infected and contaminated tissues as they relate to our regulatory responsibilities.